The Geochemical Baseline Survey of the Environment (G-BASE) project sets out to map and establish the natural geochemical baseline of the British Isles by collecting stream sediment, water, soil and more recently vegetation samples (at drainage sites) throughout the UK.

The regional geochemical baseline data are important in order to understand our environment and to measure changes, whether they be natural or human-made. This baseline data of the surface environment also allows us to model the migration of elements and provides a reference point against which we can monitor change.

The geochemical baseline stream sediment maps for the UK present data compiled from the BGS's G-BASE project and the Geological Survey of Northern Ireland's TellusNI geochemical survey. The maps are based on analyses of the <150 μm size fraction of up to 110 794 sediment samples collected from first and second order (i.e. small) streams across the UK, that have been analysed for up to 52 major and trace elements (e.g. calcium, magnesium, cobalt, nickel etc). An atlas of the element stream-sediment concentrations for the north of Ireland is available online for viewing as an ebook download.

For the rest of the UK, more detailed information on the G-BASE stream-sediment dataset, including a series of regional geochemical atlases, is available to download.

The data for 18 elements can be downloaded as a set of interpolated concentration maps (37.4 MB) on a 500 m grid across the UK.